# Add two unsigned numbers using bits

Given two unsigned integers (maximum possible input can be of 32 bits). The task is to add two numbers using bit operations.

Examples:

Input: n1 = 12, n2 = 34
Output: 46

Input: n1 = 12564 n2 = -1
Output: 12563

## Recommended: Please try your approach on {IDE} first, before moving on to the solution.

Approach: Since we know that in bit addition

• 1+0=1
• 0+1=1
• 0+0=0
• 1+1=0 carry 1
• if(carry==1) 1+1=1 carry 1

Represent integer using bitset function in C++ . It behaves like an array which stores the LSB (Least Significant Bit) at 0th index and when we print such an array it prints the binary representation in reverse format. Add every bit from right according to the bits addition property and store in the third bitset. Function to_ulong() is used to convert a bitset form into its decimal form.

Below is the implementation of the above approach.

## C++

 #include #define M 32 using namespace std;    // Function to add two bitset int binAdd(bitset atemp, bitset btemp) {     // To store the bits of answer     bitset ctemp;     for (int i = 0; i < M; i++)         ctemp[i] = 0;        // Initialize carry to 0     int carry = 0;        for (int i = 0; i < M; i++) {            // Both bits are zero         if (atemp[i] + btemp[i] == 0) {                if (carry == 0)                 ctemp[i] = 0;                else {                 ctemp[i] = 1;                 carry = 0;             }         }            // Any of the one bit is 1         else if (atemp[i] + btemp[i] == 1) {                if (carry == 0)                 ctemp[i] = 1;             else {                 ctemp[i] = 0;             }         }            // Both bits are 1         else {             if (carry == 0) {                 ctemp[i] = 0;                 carry = 1;             }             else {                 ctemp[i] = 1;             }         }     }        // To convert bitset into     // decimal equivalent     return ctemp.to_ulong(); }    // Driver Code int main() {     int number1, number2;     number1 = 12;     number2 = 34;        // Converting number 1 to bitset form     bitset num1(number1);        // Converting number 2 to bitset form     bitset num2(number2);        cout << binAdd(num1, num2) << endl; }

## Java

 // Java program to add two // unsigned numbers using bits import java.util.*;    class GFG { static final int M = 32;    // Function to add two BitSet static long binAdd(BitSet atemp,                    BitSet btemp) {     // To store the bits of answer     BitSet ctemp = new BitSet(M);     for (int i = 0; i < M; i++)         ctemp.set(i, false);        // Initialize carry to 0     int carry = 0;        for (int i = 0; i < M; i++)     {            // Both bits are zero         if (atemp.get(i) ==false &&             btemp.get(i) == false)          {                if (carry == 0)                 ctemp.set(i, false);                else              {                 ctemp.set(i, true);                 carry = 0;             }         }            // Any of the one bit is 1         else if (atemp.get(i) == true||                   btemp.get(i) == true)          {                if (carry == 0)                 ctemp.set(i, true);             else              {                 ctemp.set(i, false);             }         }            // Both bits are 1         else          {             if (carry == 0)             {                 ctemp.set(i, false);                 carry = 1;             }             else              {                 ctemp.set(i, true);             }         }     }        // To convert BitSet into     // decimal equivalent     return ctemp.toLongArray()[0]; }    // Driver Code public static void main(String args[]) {     int number1, number2;     number1 = 12;     number2 = 34;        // Converting number 1 to BitSet form     BitSet num1 = BitSet.valueOf(new long[]{number1});            // Converting number 2 to BitSet form     BitSet num2 = BitSet.valueOf(new long[]{number2});        System.out.println(binAdd(num1, num2) ); } }    // This code is contributed // by Arnab Kundu

## Python3

 # Python3 implementation of the approach    # Function to convert given Integer # to list of bits of length M def bitset(num):            return [int(x) for x in format(num, '032b')]        # Function to add two bitset  def binAdd(atemp, btemp):         # To store the bits of answer      ctemp = [0] * M             # Initialize carry to 0      carry = 0     for i in range(0, M):             # Both bits are zero          if atemp[i] + btemp[i] == 0:                 if carry == 0:                 ctemp[i] = 0                else:                  ctemp[i] = 1                 carry = 0                        # Any of the one bit is 1          elif atemp[i] + btemp[i] == 1:                 if carry == 0:                 ctemp[i] = 1             else:                  ctemp[i] = 0            # Both bits are 1          else:             if carry == 0:                  ctemp[i] = 0                 carry = 1                            else:                 ctemp[i] = 1                    # To convert bitset into string and then      # convert string to its decimal equivalent      temp = ''.join([str(x) for x in ctemp])     return int(temp, 2)        # Driver Code  if __name__ == "__main__":         number1, number2 = 12, 34     M = 32            # Converting number 1 to bitset form      num1 = bitset(number1)         # Converting number 2 to bitset form      num2 = bitset(number2)         print(binAdd(num1, num2))        # This code is contributed by Rituraj Jain

Output:

46

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